Restart your computer in Safe Mode
Turn off/disable Remote Desktop Connection (RDC) and Terminal Services

Right click My Computer and click Properties
Click on the Remote tab at the top of the window
UNCHECK the box next to, “Allow users to connect remotely to this computer“
Click OK
Go to Start -> Control Panel -> Administrative Tools -> Services
Find Terminal Services
Right click on Terminal Services and click Properties
In the Startup Type box, select Disabled
Click OK to close the window

Replace the Terminal Services DLL (termsrv.dll) with an unrestricted version form a previous release of Terminal Services. ((Find it on the internet))

Using a file manager like Windows Explorer open C:\Windows\system32\dllcache
Rename the file termsrv.dll to termsrv_dll.bak or whatever you would like.
Copy the downloaded termsrv.dll file (the one you just downloaded from the web) to C:\Windows\system32\dllcache
Open the C:\Windows\system32 folder
Delete the file termsrv.dll in C:\Windows\system32

Edit the Windows Registry to enable more than one RDP connection.

Go to Start -> Run and type regedit
Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\Licensing Core
Add a DWORD Key named EnableConcurrentSessions and give it a value of 1
Close the Registry Editor window

Use Group Policy Editor
Go to Start -> Run and type gpedit.msc
Browse to Computer Configuration -> Administrative Templates -> Windows Components -> Terminal Services and double click Limit number of connections
Select the Enabled button and enter the number of connections you would like to enable?.at least 2.
Restart Windows
Right click My Computer and select Properties.
Click on the Remote tab at the top of the window
CHECK the box next to, “Allow users to connect remotely to this computer“
Click OK
Go to Start -> Control Panel ->Administrative Tools -> Services. Select Terminal Services from the list and double click it or right-click -> Properties. Set the Startup Type to Manual.

Restart Windows/Computer